The present invention relates to methods and apparatus for delivering a medical instrument to a diagnostic and/or treatment site within the body of a patient. More particularly, the present invention simplifies diagnosis and treatment of a variety of ailments by enabling accurate placement of surgical and/or diagnostic tools in areas not directly visible to a surgeon during a medical procedure.
Surgical treatment of tumors and other conditions usually involve a first set of procedures undertaken for diagnostic purposes, followed, often at a different place and on a different day, by a second set of procedures for more detailed diagnosis and/or for treatment of a condition detected by the first set of procedures.
Location information transfer between diagnostic phase procedures and treatment phase procedures involves intrinsic difficulties: an organ inspected at a first time in a first position under an imaging modality such as an imaging probe (e.g. an ultrasound probe) may look completely different when inspected during further diagnostics or treatment, perhaps days later, with patient in a more or less different position, the organ subject to somewhat different weights and pressures, the imaging equipment being somewhat differently positioned, etc. According to methods of prior art it is standard practice to re-do various diagnostic procedures (e.g. diagnostic imaging) on the day of treatment (e.g. ablative surgery) rather than attempting to use previously gathered location information to guide a surgical procedure, despite disadvantages of inefficiency through repetition of time-consuming procedures, additional exposures to ionizing radiation, exposure to radioactive elements, and various other inconveniences. Some physicians also base treatment on previously gathered location information adjusted to the changed situation of a later treatment session merely according to the physician's impression based only on limited information such as printed records of 2D ultrasound images.
When repetition of diagnostic procedures is not convenient or not practical, surgeons lacking means to relate diagnostic-phase information to a real-time treatment context usually choose to “err on the side of caution” and to ablate healthy tissues along with pathological tissues, because of lack of an efficient means of distinguishing between the two at the time of treatment.
Such has been clinical practice, for example, in prostate surgery. According to prior art methods, once a cancer of the prostate is diagnosed, standard clinical procedure has been to ablate all or most of the prostate, thereby assuring that all the cancer has been destroyed. It has been suggested that one reason for this standard clinical practice has been that detection and localization of specific malignant sites within a prostate is difficult to do: once a problematic site has been identified during a first (diagnostic) procedure, the generally soft and flexible nature of prostate tissue is such as to render it difficult for a surgeon to accurately return to that detected and diagnosed site during a second (ablative) procedure.
The percentage of men who will develop prostate cancer in their lifetime is extremely high. Once a prostate cancer is detected, it is common clinical practice to ablate most or all of the prostate, in order to be sure that all malignant portions of the prostate have been destroyed. Yet, there are several known disadvantages to general ablation of most or all of a prostate. Prostate surgery not infrequently results in damage to the neurovascular bundle, to the urethra and the urethral sphincters, to the rectum, and to various other healthy and potentially important tissues in the neighborhood of the prostate. Damage to such tissues can lead to incontinence, to impotence, and to a variety of other complications ranging from the merely uncomfortable, through those which retard recovery, to those which comprise serious long-term or permanent deleterious effects on patients' length of life and quality of life.
It is noted that there exists a diagnostic procedure for detecting prostate cancer known in the art as “saturation biopsy”, comprising taking numerous tissue samples from throughout the prostate. Perhaps because prior art clinical practice generally calls for ablation of most or all of the prostate once a cancer has been detected, saturation biopsy as currently practiced does not comprise maintaining accurate records of the positions of source sites of each individual tissue sample, and indeed generally involves mixing or combining of tissues taken from several sites prior to diagnostic pathological examination of the tissues.
Saturation biopsy performed through the perineum requires anesthesia, either general anesthesia or a periprostatic block. Therefore more than about 95% of the prostate biopsies are performed via the rectum by “blind” free-hand insertion of the biopsy needle via a needle guide mounted on a TRUS transducer, or via a cannula passing through a TRUS transducer. Though the procedure may be performed under ultrasound guidance, the physician has only rough and estimated information as to the location from which each biopsy has been taken. Records for the biopsy locations by means of TRUS records under these circumstances are not accurate and are largely useless, and in practice are not used in subsequent procedures